The use of nano particles, such as quantum dots (QD), for lighting applications is known in the art. US20110240960, for instance, describes a light emitting device comprising a light emitting source, a first quantum dot wavelength converter disposed above the light emitting source, the first quantum dot wavelength converter comprising a plurality of first quantum dots for generating wavelength-converted light by converting wavelength of light from the light emitting source, a first dispersive medium embedding the first quantum dots dispersively therein, and a first sealer for sealing the entire outside surface of dispersive medium embedding the first quantum dots in a pack.
A first encapsulant is applied for encapsulating the entire outside surface of the first quantum dot wavelength converter. Further, a second quantum dot wavelength converter is disposed above the first quantum dot wavelength converter, the second quantum dot wavelength converter comprising a plurality of second quantum dots for generating wavelength-converted light by converting wavelength of light from the light emitting source, a second dispersive medium embedding the second quantum dots dispersively therein, and a second sealer for sealing the entire outside surface of the second dispersive medium embedding the second quantum dots in a pack, wherein the first quantum dot wavelength converter, the second quantum dot wavelength converter and the light emitting source are spaced apart from each other. The second encapsulant is deposited on the entire outside surface of the second quantum dot wavelength converter and for encapsulating the entire outside surface of the second quantum dot wavelength converter. Further, the light emitting source is a light emitting diode or a laser diode.
WO2014/064555 provides a process for the production of a wavelength converter containing a siloxane polymer matrix with wavelength converter nano particles embedded therein, the process containing (a) mixing (i) a first liquid containing (i1) short chain siloxane polymers and (i2) wavelength converter nano particles having an outer surface grafted with siloxane grafting ligands and (ii) curable siloxane polymers, and (b) curing the curable siloxane polymers, thereby producing the wavelength converter(100); wherein the short chain siloxane polymers have s1 Si backbone elements, wherein the siloxane grafting ligands comprise siloxane grafting ligands having x1 Si backbone elements, wherein at least one Si backbone element of each siloxane grafting ligand comprises a group having a grafting functionality; and wherein the curable siloxane polymers have y1 Si backbone elements, wherein x1/s1>=0.8, s1<y1 and wherein x1<y1.
WO2014/064620 provides a process for the production of a light converter comprising a siloxane polymer matrix with light converter nano particles embedded therein, the process comprising (a) mixing (i) light converter nano particles having an outer surface grafted with grafting ligands and (ii) curable siloxane polymers, and (b) curing the curable siloxane polymers, thereby producing the light converter; wherein the grafting ligands comprise siloxane grafting ligands having x1 Si backbone elements, wherein at least one Si backbone element of each siloxane grafting ligand comprises a side group having a grafting functionality; wherein the curable siloxane polymers have y1 Si backbone elements; and wherein x1 is at least 20, wherein y1 is at least 2, and wherein x1/y1>=0.8.